In the middle of the last night of January 2018, Mossad agents broke into a secret vault on the outskirts of Tehran, while their commanders watched from afar. The agents encountered an unexpected problem, a “rich people problems,” according to a person familiar with the details of the operation.

The large room contained 32 huge Iranian-made safes, each 2.7 meters in height. The safes were loaded onto heavy container-like installations, on wheels that can carry massive weight.

The documents were secreted behind two different doors—a heavy iron door inside the facility and another iron door equipped with an alarm system and cameras at the facility’s exterior wall.

This is where the Iranian Ministry of Defense decided to keep one of the greatest secrets of the Islamic Republic. In fact, only a handful of people in Iran even knew that the Iranian nuclear archive was inside this warehouse, in the heart of a sleepy suburb in the capital.

But it did not remain a secret.

The agents knew how to disable the alarm system and break through the iron doors, but they also knew they did not have time to break into all the safes. They would have to make do with less than ten, and look for three types of folders: those containing Iran’s correspondence with the International Atomic Energy Agency (IAEA); those detailing the construction of nuclear sites and acquisition of nuclear equipment; and most importantly, those detailing the design and production of the nuclear warhead (which has never been completed).

But then, inside the safes’ room, agents found something else, besides folders: CDs, piles of them—a massive amount of DVDs and computer discs, most of them unmarked.

So what the hell were they going to do now? Should they ignore the potential secrets these CDs may hold? Or take a calculated risk with a new variable that might complicate the operation? The agents received an explicit order from the command room: take everything, including the CDs.

At one minute to five in the morning, the agents left the warehouse. When the break-in was discovered, about 12,000 Iranian security personnel went on the pursuit in an attempt to figure out who stole the nuclear archive from under their noses.

In the end, despite the unexpected piles of CDs, all of the material was extracted from Iran, and no one got caught. The Iranians could only guess who was behind the heist, but until Prime Minister Benjamin Netanyahu’s famous press conference on April 30, they didn’t know for sure what really happened to “the filthy secrets of the Iranian regime,” as dubbed by Mossad director Yossi Cohen.

A few weeks later, when the material arrived in Israel, dozens of translators, experts and analysts—assisted by Persian speakers from Israel’s Military Intelligence Directorate’s (MID) Unit 8200—started digging through the piles of material. It was then that it became clear how important was the decision to risk everything and take the CDs.

The written material comprises of 114 folders, containing more than 55,000 pages, of which 8,500 were handwritten documents, many of them authored by senior government officials, and some by nuclear personnel who died in operations attributed to the Mossad.

But the biggest surprise was the massive amount of information stored in the 182 disks. A Mossad case officer told me he would have paid hundreds of thousands of dollars for one CD like this.

The Iranians documented everything: the equipment, the construction of secret plants and sites, the experiments, detailed presentations on the project’s progress, goals and stages, and even themselves, during nuclear experiments.

The bottom line is clear: it was a mega-scam, a state-level deception, in which senior Iranian officials and hundreds of others have taken part for years.

For two decades, Iran denied having a military nuclear program. But the contents of the safes tell a different story, a completely different and undeniable account: for years, Iran has been engaged in a covert nuclear project aimed at producing five nuclear bombs, with a yield of 10 kilotons each. And this was only stage one.

According to a Western intelligence source, “over the years, we have seen all sorts of programs, but we have not always understood their overall context. Until we saw these documents, we didn’t really understand how projects that were part of AMAD (the secret project’s code name—RB) were translated into secret projects under the Ministry of Defense, or open projects with a hidden agenda within SPAND (the later, public name, of the project—RB). The material Israel had obtained solved these mysteries.”

“The sweeping Iranian denial “is really comical at this point,” the source added.

The documents don’t just expose the Iranians’ deceit. It also demonstrates the weakness of the Treaty on the Non-Proliferation of Nuclear Weapons (NPT), which Iran signed and the IAEA failed to enforce.

The archives show that under the UN agency’s nose—despite repeat warnings, the information obtained by the Mossad and other espionage agencies, and media exposés—Iran has succeeded in conducting a secret military nuclear program over a long period of time (and Israel claims Tehran continues to do so even today).

Iran continues to deny everything even now; claiming the entire story of the seized archive is fabricated and serves an Israeli-American agenda aimed at canceling the nuclear agreement. This response was to be expected. What might have been less predictable is the lukewarm international response to the material uncovered in the Israeli operation.

The reactions ranged from claims the material was “old news” to assertions it does not uncover any “smoking guns” to prove Iran is currently violating the nuclear agreement.

But if the Islamic Republic is not violating or planning to violate the agreement, why keep such a detailed archive allowing Iran to resume its nuclear effort from where it left off (assuming they actually stopped)?

For many years Israel, the United States, France, Britain and Germany have been collecting intelligence about the Iranian nuclear project. Some of this material has been handed to the IAEA over time in the hopes it would provoke an appropriate response. The intelligence gathered was classified by the IAEA into 12 different topics— referred to as “the PMD,” the acronym for “Possible Military Dimensions”— each depicting research, production or other experiments related to the bomb.

Over the years, Iran has vehemently denied dealing with any of these topics. The condition for signing the nuclear agreement was that Iran would make a full disclosure of its progress in each of the 12 PMD issues. Before signing the agreement, Yukiya Amano, the Japanese diplomat who heads the IAEA, promised senior Israeli officials, according to their testimony, that “he will never sign the deal” before receiving satisfactory answers on all 12 topics.

At the end of 2015, Amano published a report practically accepting the Iranian denial of ever having a military nuclear project. Now, in light of the material discovered by the Mossad, it appears his report was based on false information.

The intelligence uncovered in the operation was revealed to the Americans, the Chinese, the Russians, the French, the British, the Germans, and of course to IAEA officials.

With the exception of the US (and, of course, Israel), it seems the world wasn’t floored by the discoveries, and Amano himself has kept quiet.

This is despite the fact that the sensitive material includes documentation of advanced stages of practical field research, experiments and timetables for the production of an atomic bomb and its adaptation to the warhead of the long-range Shahab ballistic missile.

Holger Stark, the deputy editor of the German Die Zeit newspaper, contacted the IAEA in Vienna for a response. The agency refused to comment.

Quite a lot has been written about the Mossad operation. However, media reports in Israel and abroad dealt less with the archive itself, and more with the difficult questions it poses.

Here is a glimpse into the secret intelligence gathered from Iran’s safes room. These are the facts; the questions they raise are for the world to answer.

The scientists

So what is this “Iranian nuclear archive” that Mossad agents managed to transport thousands of kilometers, all the way to Israel?

Iran’s secret military nuclear program began to take shape in 1992 or 1993, when the Iranians became interested in acquiring technologies for the production and operation of centrifuges for uranium enrichment. Tehran acquired much of its knowledge from Pakistan’s nuclear project director, Abdul Qadeer Khan, and later from other elements, some of them Chinese.

The first centrifuges were designed at a site called Damāwand. Israel warned the international community about the construction of the nuclear enrichment facility, so Iran decided to dismantle it and build another one in its stead.

This was the site that would later become well known, the Natanz nuclear facility. In internal Iranian documents, the site was called “Kashan,” and it houses an increasing number of centrifuges.

At first, Israel was alone in its intelligence campaign against Iran. The intelligence it brought to the attention of IAEA and Western countries was greeted with indifference. Even the United States failed to act at first, and didn’t recognize the authenticity or the importance of the material the Mossad collected on Iran. Only at a later stage, when intelligence ties with Israel strengthened and additional information about Kashan was brought to their attention did the Americans start to act.

Meanwhile, the Iranians secretly set up their military program to produce an atomic bomb, entitled “The AMAD Project.”

Who gave the orders? This is one question the archive answers unequivocally: the Iranian leadership. The material does not include direct instructions from Supreme Leader Ayatollah Ali Khamenei, who, after strongly denying that Iran has a nuclear program, apparently made sure his name will not be tied to the project. Nevertheless, the archive contains, without doubt, documents signed by the defense minister at the time and current Secretary of the Supreme National Security Council, Ali Shamkhani.

And he’s not alone. “The plan was approved by the Cognitive Sciences and Technologies Council,” the header of one document states. This is a codename for the senior group of executives who manage Project AMAD, which included the president at the time, Mohammad Khatami; then-head of the Supreme National Security Council, Hassan Rouhani (the current Iranian president); then-Defense Minister Ali Shamkhani; and the head of the Atomic Energy Organization of Iran (AEOI) at the time, Gholam Reza Aghazadeh.

So what is the purpose of the AMAD Project? The answer to this question too can be found in the archive. According to the material obtained in the Mossad operation, the Iranian plan is to produce five warheads with a yield of 10 kilotons each, and develop the ability to assemble these warheads on the Iranian-made Shahab 3 missile.

Incidentally, nuclear experts who examined the documents say that the Iranian leaders’ plan lays out far more extensive infrastructure than what is needed to produce “only” five bombs.

The making of a nuclear bomb and the ability to launch it is a very complex project that requires a state effort and coordination between all Iranian army and intelligence forces.

One particularly colorful presentation, which was discovered in one of the CDs, shows the complexity of the Iranian nuclear project. According to the presentation, the plan is based on a joint effort of various Iranian bodies: the Intelligence Ministry, the Islamic Revolutionary Guard Corps (including its Aerospace Force), and the Quds Force—the Guards’ secret unit, which is currently waging war with Israel at the Syrian border.

The documents mention time and again the person who is both the manager and the brains behind the nuclear program—Prof. Mohsen Fakhrizadeh. The nuclear archive includes countless documents with Fakhrizadeh’s signature, including documents addressed to him, or approved by him.

For example, one letter addressed to Fakhrizadeh, dated January 19, 2001, and written by the director of the explosive mechanism developing team, delineates a long list of features needed to fit the mechanism to the rest of the nuclear bomb (which is comprised of numerous parts). Fakhrizadeh thanked the director at the bottom of his letter and gave him further instructions.

According to foreign media reports, Israel considered Fakhrizadeh as a preferred target for intelligence gathering, and even seriously considered harming him, especially during the tenure of former prime minister Ehud Olmert and the late Mossad director Meir Dagan. Since Fakhrizadeh is still alive, the assassination plan has yet to materialize. It appears Olmert decided to halt the operation, and so Fakhrizadeh’s life was spared. If the former prime minister is indeed behind such a decision, there are those who to this day believe it was a mistake.

However, someone—Iranian intelligence sure it was the Mossad—was able to reach various Iranian nuclear scientists whose names appear in the seized documents.

In his handwriting, Dr. Fereydoon Abbasi-Davani, a senior nuclear program official, inscribes a long technical document to Fakhrizadeh, who replied at length.

Dr. Abbasi-Davani is the Chair of the physics department at Tehran’s Imam Hossein University and a key figure in Iran’s nuclear program. On November 29, 2010, his colleague Majid Shahriari was assassinated.

An assassin on a motorbike tried to kill Davani as well by attaching a bomb to his car window while he was driving, but Davani managed to escape at the last minute and survived. Iran’s president at the time, Mahmoud Ahmadinejad, appointed Davani as his deputy to show his appreciation for the doctor’s “contribution to the Islamic Republic and for his courage.”

One may feel some discomfort when diving into the piles of Iranian documents, since there’s something eerie about them. For example, the radical state’s dream of creating weapons of mass destruction becomes an orderly and meticulous timeline in Microsoft Project, including information on the program’s budgets, personnel, experiments, and more.

At times, the nuclear documents receive a more personal flair. For instance, in one of the archive’s CDs, agents found “selfie” photos of an Iranian nuclear expert, the heavyset Dr. Mahdi Tranchi, wearing protective goggles and posing for the camera at the “Taleqan 1” nuclear test site.

What happened to all this effort? All those people, information, and experience gathered? Did they all just disappear?

The nuclear sites

It was not only the people who worked on the Iranian nuclear project that the documents expose. They also expose the places and sites where the nuclear plot was devised, some of which were new discoveries for the Israeli intelligence community (“I wish I had this information in real time,” said a former Israeli intelligence chief when exposed to the material), including nuclear experiment sites, uranium mines located across the country, tunnels (dug to cover up their real purpose), and more.

According to the material, the Iranians were looking for an underground nuclear testing site. It goes without saying that to conduct such an experiment, they needed to first build a bomb, which the Iranians have not yet done.

Furthermore, a nuclear experiment does not depend solely on scientific ability, but mostly on the decision of the political leadership. An underground experiment would have certainly been detected by the West. Such a test would essentially constitute a declaration by Tehran that it had indeed developed a bomb.

In the meantime, until the Iranians develop a nuclear bomb, the Iranians are getting ready, and according to the documents they have already examined various possible sites and even attempted to detonate small explosives deep underground to test the ground, its durability and their own ability to record the measurements of the explosion at that location.

The Israeli intelligence community also discovered new information about some known nuclear sites. For example, the site in Fordow, near the city of Qom, is well hidden at the heart of the mountain, and is extremely resistant to bombs.

The Israeli, French, and American intelligence communities exposed it in 2010, but the archive’s documents established its importance as part of the Ghadir Project (another code name for the Iranian secret nuclear program).